ATHENS • At least four people have died and a desperate effort was under way yesterday to find hundreds more believed missing after a migrant boat capsized off the Greek island of Crete, the coastguard said.

Coastguard spokesman Nikos Lagadianos said at least 340 people had been rescued, and the International Organisation for Migration (IOM) said the vessel "is believed to have left Africa with at least 700 migrants on board". It was the second migrant vessel found in that area of the southern Aegean Sea since last week, indicating that people smugglers may be forging a new route to avoid Nato ships.

A coastguard spokesman told news agency Agence France-Presse that a major rescue operation was underway, including four ships that were passing through the area, in clear but windy conditions about 75 nautical miles south of Crete.

It was not immediately clear where exactly the boat had left from or where it was headed, or the nationalities of those on board. The spokesman said a passing ship spotted the sinking vessel off Crete.

The coastguard rushed two patrol boats, a plane and helicopter to the scene. About half of the 25m-long boat was completely underwater, the spokesman said.

The deaths are the first in Greek waters since April, as a controversial March deal between the European Union (EU) and Turkey, designed to halt the flow of migrants using the popular Aegean route, has led to a sharp drop in traffic.

Greek tourist islands in the Aegean witnessed the arrival of hundreds of thousands of people crossing in flimsy boats from nearby Turkey last year, many of them refugees fleeing the war in Syria.

But the number of people using that route has reduced to a trickle after the EU-Turkey deal, under which migrants landing on the islands can be sent back to Turkey, as well as the deployment of Nato ships in the Aegean.

The IOM said its observations supported the theory of a possible new migrant route, reporting a "surge of new arrivals to Greece further south, on sea lanes connecting North Africa to the island of Crete".

AGENCE FRANCE PRESSE